cpu overloading

[okliv]

hi!

i have

Version: ImageMagick 6.7.5-3 2012-02-23 Q16 http://www.imagemagick.org
Copyright: Copyright (C) 1999-2012 ImageMagick Studio LLC
Features: OpenMP

installed

my linux is gentoo (i've compiled from source)

when i call convert image.jpg -scale 50% image-small.jpg everything goes ok but
when i call convert image.jpg -resize 64x64 image-small.jpg all my server cpus jump up to 100% and this process take upto 10 seconds

is something wrong with imagemagick/server or it has to be like i described?

thanx in advance

[magick]

Add --disable-openmp to your configure script command line and rebuild / reinstall ImageMagick. Also add -define jpeg:size=64x64 to your convert command line (e.g. convert -define jpeg:size=64x64 image.jpg -resize 64x64...).

[okliv]

in fact, i've got this results because of small investigation why server hang during picture uploading with carrierwave+rmagick gems for my ruby on rails app...
in this case i do not know how to add -define jpeg:size=64x64 to rmagick incapsulated commands... is it only one possible solution, or is it only an assumption?

thanx again for quick answer

[okliv]

i reinstalled imagemagick several times with --disable-openmp key, but no luck
then i uninstalled imagemagick first and made configure/make/install again and it works now!
openmp - is evil..

[anthony]

openmp - is evil..

It is a 'good' evil... in moderation... as it is with most things evil (like broccoli ).
But if you let the evil gather in large groups it starts to warp the universe in very unexpected ways.

On its own openmp is a good idea. But only if you don't use it with other openmp processes, or even a large number of other cpu bound processes. It is not for example a good idea to have it enabled for web servers, which can run a single PHP script, many many times in parallel.